Porcelain teeth and method of making the same



July 2,1929. G. WAGNER 1.719.577

PORCELAIN TEETH AND METHOD OF MAKING THE SAME Filed-Sept. 10, 1926 luvgkron I ATTORNEY.

Patented July 2, 1929.

GEORG WAGNER, or MONSEY, NEW YORK.

PORCELAIN TEETH AND METHOD OF MAKING THE SAME Application filed September 10, 1926. Serial No. 134,587.

This invention relates to porcelain teeth and methods of making the same and more particularly pivots therefor.

Heretofore, porcelain teeth have been produced by molding the tooth into the desired erly enter the anchoring pins into the screw 1 threaded recesses formed by the matrix prior to the firing.

My invention consists in providing a stem of an alloy or composition of iron and nickel or iron and chromic nickel, or iron and cobalt nickel, which when applied to a tooth .and

subjected to the firing heat, will not melt, and

will not discolor the porcelain, and also will not be attacked by the acids of silica formed by the intense heat, but will most readily be dissolved by suitable acids used for dissolving such pivots or stems.

Such a composition does not dissolve in the silica acids formed by the heating of the porcelain nor does it melt at the firing temperature to which the porcelain and stem are subjected. It enables the porcelain toebe fired as hard as required, is heat resistant, is relatively free from oxidation, is easily soluble in dissolving acids,and is silica acid resistant.

In the firing of porcelain teeth it has been found that after the heating of the same to a certain temperature, the porcelain gradually shrinks or sinters to about one third of its size. Such shrinking oresintering has an effect upon the stem. If the stem and the screwthreads thereof and those of the porcelain, do not co-act then a warping of the tooth may result. If, however, the action of the tooth and stem under the firing heat is substantially reciprocal, then neither the tooth or screwthreads or stem is disturbed in their co-extensive relationship. I obtain this result by reason of the fact that the coefficients of expansion of the tooth and of the stem or matrix member are the same.

A composition of iron and nickel either as nickel or as chromic nickel or as cobalt nickel, with the nickel constituent as 2% either as nickel, or chromic nickel or cobalt nickel, gives excellent results. This proportion may be varied as more or less than 2% of nickel constituent. The maximum may range as high as 5% and the minimum as low as but as this maximum or minimum is I approached, the disadvantages pointed out may become more or less evident. A 2% nickel iron composition enables the stem to successfully meet the higher temperatures of baking, and'a unity of action between porce- 1am and stem is present, resulting in "good products free from discoloration. The flux of the silica of the porcelain resulting'from the firing does not act upon such a stem.

WVhile an iron stem may wilt at about 1000 F., and a nickel stem at about 1200 F.-, my improved. composition stem will withstand a heat of 1400 F.

.An object of the presentinvention is to support the walls of the screw threaded recesses during thefiring process, in order to overcome any tendency of the threads or walls of the recesses to become warped or otherwise deformed.

Another object of this invention is to pre vent breakage of the porcelain tooth body should the same contact with, a hard substance. when in use.

Another object of this invention is to pre- 85 vent electrolytic action between the metallic backing plate of the artificial tooth and, the attaching screw therefor. a A feature of the present invention is the backing plate for the porcelain body which projects around-the outer end of the porce lain body to. form a metallic cuttingedge which will effectively protect the porcelain from breaking.

Another feature of the invention is the method of preventing the metallic anchoring pin from contacting with the metallic backing plate and setting up electrolytic action within the mouth of the user.

A further feature of the present invention 100 is the matrix for holding the screw threads in proper form during the firing process and the substance from which such matrices are produced, so that they will have the same coefficient of expansion as the body of the tooth, 105 whereby a perfect product is insured.

A still further feature of the invention is the facility with which the matrix may be removed from the cavity without injury to the threads formed therein.

In the drawings,

Figure 1 is a sectional view of my improved porcelain tooth with interior screw threads, and

Figure 2 is a side view of my improved screw,

Fi ure 3 is a View similar to Figure 1 showing the completed tooth ready to be applied, and

Figure 4 is a rear view of the Figure 1.

Similar characters of reference indicate corresponding parts.

Referring to the drawings, the tooth 10 has interior screwthreads 11. When the tooth has the provisional stem dissolved therefrom it has the appearance of Figure 1.

The tooth is now ready to be applied to the gum of the user It is in addition to the screwthreaded portion 11, provided with an outwardly flaring portion 15 extending circumferentially around the screw threaded opening. The improved stem has its shank portion 12 constricted in respect to the screw threaded portion 13, and has the bevelled head 14, flat at the outside as at 16 and bevelled on the inside as at 17 A gold plate 20 is then applied to the tooth 10, which in turn is applied to a bridge (not shown) and this plate extends over the cutting edge 21 of the tooth, and itself forms a cutting edge 22, the plate hugs the tooth as shown. It has an opening 23 larger than the shank 12 so that the metallic shank does not contact with the gold or metal of the plate 20. Such I claim as new:

1. In combination, a tooth having a screwthreaded recess, which is countersunk at its outer end, a metallic plate huggingly engaging one side and cutting edge of the tooth and itself forming a cutting edge, and having an opening and a bevelled recess in line with the recess of the tooth, a stem having a screwthreaded portion engaging the screw threaded portion of the tooth, and smaller than the same and smaller than the opening of the plate, and having a head seated in the bevelled recess of the plate, and an insulating layer interposed between the stem and plate.

2. An artificial tooth comprising, in combination, a body portion of porcelain having a screw-threaded recess extending inwardly from its rear surface, a metallic plate overlying said rear surface and provided with a countersunk aperture in line with the screwthreaded recess of the porcelain body, said aperture being of larger diameter than said recess, and av fastening screw having a threaded stem engaging in the threaded recess and a head disposed in the countersunk portion of the recess, said fastening screw being free from contact with the metallic plate.

3. The herein described method of making artificial teeth with an internal screw thread bore, which consists in molding a tooth in the desired shape and embedding therein a screw-threaded matrix of an alloy including iron and nickel which alloy has substantially the same coeficient of expansion during the heat of the baking as that of the material of which said tooth is made, baking said tooth with the matrix therein, dissolving the matrix from the tooth so as to leave a bore therein having accurate internal screwthreads corresponding with screw threads of the dissolved matrix and adapted to be en- 'gaged by an accurately threaded fastening device. 7

In testimony that I claim the foregoing as my invention, I have signed my, name hereto.

GEORG WAGNER. 

